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UBUNTU: Ubuntu-4.15.0-96.97
[mirror_ubuntu-bionic-kernel.git] / tools / perf / util / probe-finder.c
1 /*
2 * probe-finder.c : C expression to kprobe event converter
3 *
4 * Written by Masami Hiramatsu <mhiramat@redhat.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19 *
20 */
21
22 #include <inttypes.h>
23 #include <sys/utsname.h>
24 #include <sys/types.h>
25 #include <sys/stat.h>
26 #include <fcntl.h>
27 #include <errno.h>
28 #include <stdio.h>
29 #include <unistd.h>
30 #include <stdlib.h>
31 #include <string.h>
32 #include <stdarg.h>
33 #include <dwarf-regs.h>
34
35 #include <linux/bitops.h>
36 #include "event.h"
37 #include "dso.h"
38 #include "debug.h"
39 #include "intlist.h"
40 #include "util.h"
41 #include "strlist.h"
42 #include "symbol.h"
43 #include "probe-finder.h"
44 #include "probe-file.h"
45 #include "string2.h"
46
47 /* Kprobe tracer basic type is up to u64 */
48 #define MAX_BASIC_TYPE_BITS 64
49
50 /* Dwarf FL wrappers */
51 static char *debuginfo_path; /* Currently dummy */
52
53 static const Dwfl_Callbacks offline_callbacks = {
54 .find_debuginfo = dwfl_standard_find_debuginfo,
55 .debuginfo_path = &debuginfo_path,
56
57 .section_address = dwfl_offline_section_address,
58
59 /* We use this table for core files too. */
60 .find_elf = dwfl_build_id_find_elf,
61 };
62
63 /* Get a Dwarf from offline image */
64 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
65 const char *path)
66 {
67 int fd;
68
69 fd = open(path, O_RDONLY);
70 if (fd < 0)
71 return fd;
72
73 dbg->dwfl = dwfl_begin(&offline_callbacks);
74 if (!dbg->dwfl)
75 goto error;
76
77 dwfl_report_begin(dbg->dwfl);
78 dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
79 if (!dbg->mod)
80 goto error;
81
82 dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
83 if (!dbg->dbg)
84 goto error;
85
86 dwfl_report_end(dbg->dwfl, NULL, NULL);
87
88 return 0;
89 error:
90 if (dbg->dwfl)
91 dwfl_end(dbg->dwfl);
92 else
93 close(fd);
94 memset(dbg, 0, sizeof(*dbg));
95
96 return -ENOENT;
97 }
98
99 static struct debuginfo *__debuginfo__new(const char *path)
100 {
101 struct debuginfo *dbg = zalloc(sizeof(*dbg));
102 if (!dbg)
103 return NULL;
104
105 if (debuginfo__init_offline_dwarf(dbg, path) < 0)
106 zfree(&dbg);
107 if (dbg)
108 pr_debug("Open Debuginfo file: %s\n", path);
109 return dbg;
110 }
111
112 enum dso_binary_type distro_dwarf_types[] = {
113 DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
114 DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
115 DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
116 DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
117 DSO_BINARY_TYPE__NOT_FOUND,
118 };
119
120 struct debuginfo *debuginfo__new(const char *path)
121 {
122 enum dso_binary_type *type;
123 char buf[PATH_MAX], nil = '\0';
124 struct dso *dso;
125 struct debuginfo *dinfo = NULL;
126
127 /* Try to open distro debuginfo files */
128 dso = dso__new(path);
129 if (!dso)
130 goto out;
131
132 for (type = distro_dwarf_types;
133 !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
134 type++) {
135 if (dso__read_binary_type_filename(dso, *type, &nil,
136 buf, PATH_MAX) < 0)
137 continue;
138 dinfo = __debuginfo__new(buf);
139 }
140 dso__put(dso);
141
142 out:
143 /* if failed to open all distro debuginfo, open given binary */
144 return dinfo ? : __debuginfo__new(path);
145 }
146
147 void debuginfo__delete(struct debuginfo *dbg)
148 {
149 if (dbg) {
150 if (dbg->dwfl)
151 dwfl_end(dbg->dwfl);
152 free(dbg);
153 }
154 }
155
156 /*
157 * Probe finder related functions
158 */
159
160 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
161 {
162 struct probe_trace_arg_ref *ref;
163 ref = zalloc(sizeof(struct probe_trace_arg_ref));
164 if (ref != NULL)
165 ref->offset = offs;
166 return ref;
167 }
168
169 /*
170 * Convert a location into trace_arg.
171 * If tvar == NULL, this just checks variable can be converted.
172 * If fentry == true and vr_die is a parameter, do huristic search
173 * for the location fuzzed by function entry mcount.
174 */
175 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
176 Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
177 unsigned int machine,
178 struct probe_trace_arg *tvar)
179 {
180 Dwarf_Attribute attr;
181 Dwarf_Addr tmp = 0;
182 Dwarf_Op *op;
183 size_t nops;
184 unsigned int regn;
185 Dwarf_Word offs = 0;
186 bool ref = false;
187 const char *regs;
188 int ret, ret2 = 0;
189
190 if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
191 goto static_var;
192
193 /* TODO: handle more than 1 exprs */
194 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
195 return -EINVAL; /* Broken DIE ? */
196 if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
197 ret = dwarf_entrypc(sp_die, &tmp);
198 if (ret)
199 return -ENOENT;
200
201 if (probe_conf.show_location_range &&
202 (dwarf_tag(vr_die) == DW_TAG_variable)) {
203 ret2 = -ERANGE;
204 } else if (addr != tmp ||
205 dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
206 return -ENOENT;
207 }
208
209 ret = dwarf_highpc(sp_die, &tmp);
210 if (ret)
211 return -ENOENT;
212 /*
213 * This is fuzzed by fentry mcount. We try to find the
214 * parameter location at the earliest address.
215 */
216 for (addr += 1; addr <= tmp; addr++) {
217 if (dwarf_getlocation_addr(&attr, addr, &op,
218 &nops, 1) > 0)
219 goto found;
220 }
221 return -ENOENT;
222 }
223 found:
224 if (nops == 0)
225 /* TODO: Support const_value */
226 return -ENOENT;
227
228 if (op->atom == DW_OP_addr) {
229 static_var:
230 if (!tvar)
231 return ret2;
232 /* Static variables on memory (not stack), make @varname */
233 ret = strlen(dwarf_diename(vr_die));
234 tvar->value = zalloc(ret + 2);
235 if (tvar->value == NULL)
236 return -ENOMEM;
237 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
238 tvar->ref = alloc_trace_arg_ref((long)offs);
239 if (tvar->ref == NULL)
240 return -ENOMEM;
241 return ret2;
242 }
243
244 /* If this is based on frame buffer, set the offset */
245 if (op->atom == DW_OP_fbreg) {
246 if (fb_ops == NULL)
247 return -ENOTSUP;
248 ref = true;
249 offs = op->number;
250 op = &fb_ops[0];
251 }
252
253 if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
254 regn = op->atom - DW_OP_breg0;
255 offs += op->number;
256 ref = true;
257 } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
258 regn = op->atom - DW_OP_reg0;
259 } else if (op->atom == DW_OP_bregx) {
260 regn = op->number;
261 offs += op->number2;
262 ref = true;
263 } else if (op->atom == DW_OP_regx) {
264 regn = op->number;
265 } else {
266 pr_debug("DW_OP %x is not supported.\n", op->atom);
267 return -ENOTSUP;
268 }
269
270 if (!tvar)
271 return ret2;
272
273 regs = get_dwarf_regstr(regn, machine);
274 if (!regs) {
275 /* This should be a bug in DWARF or this tool */
276 pr_warning("Mapping for the register number %u "
277 "missing on this architecture.\n", regn);
278 return -ENOTSUP;
279 }
280
281 tvar->value = strdup(regs);
282 if (tvar->value == NULL)
283 return -ENOMEM;
284
285 if (ref) {
286 tvar->ref = alloc_trace_arg_ref((long)offs);
287 if (tvar->ref == NULL)
288 return -ENOMEM;
289 }
290 return ret2;
291 }
292
293 #define BYTES_TO_BITS(nb) ((nb) * BITS_PER_LONG / sizeof(long))
294
295 static int convert_variable_type(Dwarf_Die *vr_die,
296 struct probe_trace_arg *tvar,
297 const char *cast)
298 {
299 struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
300 Dwarf_Die type;
301 char buf[16];
302 char sbuf[STRERR_BUFSIZE];
303 int bsize, boffs, total;
304 int ret;
305 char prefix;
306
307 /* TODO: check all types */
308 if (cast && strcmp(cast, "string") != 0 && strcmp(cast, "x") != 0 &&
309 strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
310 /* Non string type is OK */
311 /* and respect signedness/hexadecimal cast */
312 tvar->type = strdup(cast);
313 return (tvar->type == NULL) ? -ENOMEM : 0;
314 }
315
316 bsize = dwarf_bitsize(vr_die);
317 if (bsize > 0) {
318 /* This is a bitfield */
319 boffs = dwarf_bitoffset(vr_die);
320 total = dwarf_bytesize(vr_die);
321 if (boffs < 0 || total < 0)
322 return -ENOENT;
323 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
324 BYTES_TO_BITS(total));
325 goto formatted;
326 }
327
328 if (die_get_real_type(vr_die, &type) == NULL) {
329 pr_warning("Failed to get a type information of %s.\n",
330 dwarf_diename(vr_die));
331 return -ENOENT;
332 }
333
334 pr_debug("%s type is %s.\n",
335 dwarf_diename(vr_die), dwarf_diename(&type));
336
337 if (cast && strcmp(cast, "string") == 0) { /* String type */
338 ret = dwarf_tag(&type);
339 if (ret != DW_TAG_pointer_type &&
340 ret != DW_TAG_array_type) {
341 pr_warning("Failed to cast into string: "
342 "%s(%s) is not a pointer nor array.\n",
343 dwarf_diename(vr_die), dwarf_diename(&type));
344 return -EINVAL;
345 }
346 if (die_get_real_type(&type, &type) == NULL) {
347 pr_warning("Failed to get a type"
348 " information.\n");
349 return -ENOENT;
350 }
351 if (ret == DW_TAG_pointer_type) {
352 while (*ref_ptr)
353 ref_ptr = &(*ref_ptr)->next;
354 /* Add new reference with offset +0 */
355 *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
356 if (*ref_ptr == NULL) {
357 pr_warning("Out of memory error\n");
358 return -ENOMEM;
359 }
360 }
361 if (!die_compare_name(&type, "char") &&
362 !die_compare_name(&type, "unsigned char")) {
363 pr_warning("Failed to cast into string: "
364 "%s is not (unsigned) char *.\n",
365 dwarf_diename(vr_die));
366 return -EINVAL;
367 }
368 tvar->type = strdup(cast);
369 return (tvar->type == NULL) ? -ENOMEM : 0;
370 }
371
372 if (cast && (strcmp(cast, "u") == 0))
373 prefix = 'u';
374 else if (cast && (strcmp(cast, "s") == 0))
375 prefix = 's';
376 else if (cast && (strcmp(cast, "x") == 0) &&
377 probe_type_is_available(PROBE_TYPE_X))
378 prefix = 'x';
379 else
380 prefix = die_is_signed_type(&type) ? 's' :
381 probe_type_is_available(PROBE_TYPE_X) ? 'x' : 'u';
382
383 ret = dwarf_bytesize(&type);
384 if (ret <= 0)
385 /* No size ... try to use default type */
386 return 0;
387 ret = BYTES_TO_BITS(ret);
388
389 /* Check the bitwidth */
390 if (ret > MAX_BASIC_TYPE_BITS) {
391 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
392 dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
393 ret = MAX_BASIC_TYPE_BITS;
394 }
395 ret = snprintf(buf, 16, "%c%d", prefix, ret);
396
397 formatted:
398 if (ret < 0 || ret >= 16) {
399 if (ret >= 16)
400 ret = -E2BIG;
401 pr_warning("Failed to convert variable type: %s\n",
402 str_error_r(-ret, sbuf, sizeof(sbuf)));
403 return ret;
404 }
405 tvar->type = strdup(buf);
406 if (tvar->type == NULL)
407 return -ENOMEM;
408 return 0;
409 }
410
411 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
412 struct perf_probe_arg_field *field,
413 struct probe_trace_arg_ref **ref_ptr,
414 Dwarf_Die *die_mem)
415 {
416 struct probe_trace_arg_ref *ref = *ref_ptr;
417 Dwarf_Die type;
418 Dwarf_Word offs;
419 int ret, tag;
420
421 pr_debug("converting %s in %s\n", field->name, varname);
422 if (die_get_real_type(vr_die, &type) == NULL) {
423 pr_warning("Failed to get the type of %s.\n", varname);
424 return -ENOENT;
425 }
426 pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
427 tag = dwarf_tag(&type);
428
429 if (field->name[0] == '[' &&
430 (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
431 if (field->next)
432 /* Save original type for next field */
433 memcpy(die_mem, &type, sizeof(*die_mem));
434 /* Get the type of this array */
435 if (die_get_real_type(&type, &type) == NULL) {
436 pr_warning("Failed to get the type of %s.\n", varname);
437 return -ENOENT;
438 }
439 pr_debug2("Array real type: (%x)\n",
440 (unsigned)dwarf_dieoffset(&type));
441 if (tag == DW_TAG_pointer_type) {
442 ref = zalloc(sizeof(struct probe_trace_arg_ref));
443 if (ref == NULL)
444 return -ENOMEM;
445 if (*ref_ptr)
446 (*ref_ptr)->next = ref;
447 else
448 *ref_ptr = ref;
449 }
450 ref->offset += dwarf_bytesize(&type) * field->index;
451 if (!field->next)
452 /* Save vr_die for converting types */
453 memcpy(die_mem, vr_die, sizeof(*die_mem));
454 goto next;
455 } else if (tag == DW_TAG_pointer_type) {
456 /* Check the pointer and dereference */
457 if (!field->ref) {
458 pr_err("Semantic error: %s must be referred by '->'\n",
459 field->name);
460 return -EINVAL;
461 }
462 /* Get the type pointed by this pointer */
463 if (die_get_real_type(&type, &type) == NULL) {
464 pr_warning("Failed to get the type of %s.\n", varname);
465 return -ENOENT;
466 }
467 /* Verify it is a data structure */
468 tag = dwarf_tag(&type);
469 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
470 pr_warning("%s is not a data structure nor a union.\n",
471 varname);
472 return -EINVAL;
473 }
474
475 ref = zalloc(sizeof(struct probe_trace_arg_ref));
476 if (ref == NULL)
477 return -ENOMEM;
478 if (*ref_ptr)
479 (*ref_ptr)->next = ref;
480 else
481 *ref_ptr = ref;
482 } else {
483 /* Verify it is a data structure */
484 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
485 pr_warning("%s is not a data structure nor a union.\n",
486 varname);
487 return -EINVAL;
488 }
489 if (field->name[0] == '[') {
490 pr_err("Semantic error: %s is not a pointer"
491 " nor array.\n", varname);
492 return -EINVAL;
493 }
494 /* While prcessing unnamed field, we don't care about this */
495 if (field->ref && dwarf_diename(vr_die)) {
496 pr_err("Semantic error: %s must be referred by '.'\n",
497 field->name);
498 return -EINVAL;
499 }
500 if (!ref) {
501 pr_warning("Structure on a register is not "
502 "supported yet.\n");
503 return -ENOTSUP;
504 }
505 }
506
507 if (die_find_member(&type, field->name, die_mem) == NULL) {
508 pr_warning("%s(type:%s) has no member %s.\n", varname,
509 dwarf_diename(&type), field->name);
510 return -EINVAL;
511 }
512
513 /* Get the offset of the field */
514 if (tag == DW_TAG_union_type) {
515 offs = 0;
516 } else {
517 ret = die_get_data_member_location(die_mem, &offs);
518 if (ret < 0) {
519 pr_warning("Failed to get the offset of %s.\n",
520 field->name);
521 return ret;
522 }
523 }
524 ref->offset += (long)offs;
525
526 /* If this member is unnamed, we need to reuse this field */
527 if (!dwarf_diename(die_mem))
528 return convert_variable_fields(die_mem, varname, field,
529 &ref, die_mem);
530
531 next:
532 /* Converting next field */
533 if (field->next)
534 return convert_variable_fields(die_mem, field->name,
535 field->next, &ref, die_mem);
536 else
537 return 0;
538 }
539
540 /* Show a variables in kprobe event format */
541 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
542 {
543 Dwarf_Die die_mem;
544 int ret;
545
546 pr_debug("Converting variable %s into trace event.\n",
547 dwarf_diename(vr_die));
548
549 ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
550 &pf->sp_die, pf->machine, pf->tvar);
551 if (ret == -ENOENT || ret == -EINVAL) {
552 pr_err("Failed to find the location of the '%s' variable at this address.\n"
553 " Perhaps it has been optimized out.\n"
554 " Use -V with the --range option to show '%s' location range.\n",
555 pf->pvar->var, pf->pvar->var);
556 } else if (ret == -ENOTSUP)
557 pr_err("Sorry, we don't support this variable location yet.\n");
558 else if (ret == 0 && pf->pvar->field) {
559 ret = convert_variable_fields(vr_die, pf->pvar->var,
560 pf->pvar->field, &pf->tvar->ref,
561 &die_mem);
562 vr_die = &die_mem;
563 }
564 if (ret == 0)
565 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
566 /* *expr will be cached in libdw. Don't free it. */
567 return ret;
568 }
569
570 /* Find a variable in a scope DIE */
571 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
572 {
573 Dwarf_Die vr_die;
574 char *buf, *ptr;
575 int ret = 0;
576
577 /* Copy raw parameters */
578 if (!is_c_varname(pf->pvar->var))
579 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
580
581 if (pf->pvar->name)
582 pf->tvar->name = strdup(pf->pvar->name);
583 else {
584 buf = synthesize_perf_probe_arg(pf->pvar);
585 if (!buf)
586 return -ENOMEM;
587 ptr = strchr(buf, ':'); /* Change type separator to _ */
588 if (ptr)
589 *ptr = '_';
590 pf->tvar->name = buf;
591 }
592 if (pf->tvar->name == NULL)
593 return -ENOMEM;
594
595 pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
596 /* Search child die for local variables and parameters. */
597 if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
598 /* Search again in global variables */
599 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
600 0, &vr_die)) {
601 pr_warning("Failed to find '%s' in this function.\n",
602 pf->pvar->var);
603 ret = -ENOENT;
604 }
605 }
606 if (ret >= 0)
607 ret = convert_variable(&vr_die, pf);
608
609 return ret;
610 }
611
612 /* Convert subprogram DIE to trace point */
613 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
614 Dwarf_Addr paddr, bool retprobe,
615 const char *function,
616 struct probe_trace_point *tp)
617 {
618 Dwarf_Addr eaddr;
619 GElf_Sym sym;
620 const char *symbol;
621
622 /* Verify the address is correct */
623 if (!dwarf_haspc(sp_die, paddr)) {
624 pr_warning("Specified offset is out of %s\n",
625 dwarf_diename(sp_die));
626 return -EINVAL;
627 }
628
629 /* Try to get actual symbol name from symtab */
630 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
631 if (!symbol) {
632 pr_warning("Failed to find symbol at 0x%lx\n",
633 (unsigned long)paddr);
634 return -ENOENT;
635 }
636 eaddr = sym.st_value;
637
638 tp->offset = (unsigned long)(paddr - eaddr);
639 tp->address = (unsigned long)paddr;
640 tp->symbol = strdup(symbol);
641 if (!tp->symbol)
642 return -ENOMEM;
643
644 /* Return probe must be on the head of a subprogram */
645 if (retprobe) {
646 if (eaddr != paddr) {
647 pr_warning("Failed to find \"%s%%return\",\n"
648 " because %s is an inlined function and"
649 " has no return point.\n", function,
650 function);
651 return -EINVAL;
652 }
653 tp->retprobe = true;
654 }
655
656 return 0;
657 }
658
659 /* Call probe_finder callback with scope DIE */
660 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
661 {
662 Dwarf_Attribute fb_attr;
663 Dwarf_Frame *frame = NULL;
664 size_t nops;
665 int ret;
666
667 if (!sc_die) {
668 pr_err("Caller must pass a scope DIE. Program error.\n");
669 return -EINVAL;
670 }
671
672 /* If not a real subprogram, find a real one */
673 if (!die_is_func_def(sc_die)) {
674 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
675 if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
676 pr_warning("Ignoring tail call from %s\n",
677 dwarf_diename(&pf->sp_die));
678 return 0;
679 } else {
680 pr_warning("Failed to find probe point in any "
681 "functions.\n");
682 return -ENOENT;
683 }
684 }
685 } else
686 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
687
688 /* Get the frame base attribute/ops from subprogram */
689 dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
690 ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
691 if (ret <= 0 || nops == 0) {
692 pf->fb_ops = NULL;
693 #if _ELFUTILS_PREREQ(0, 142)
694 } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
695 (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
696 if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
697 (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
698 dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
699 pr_warning("Failed to get call frame on 0x%jx\n",
700 (uintmax_t)pf->addr);
701 free(frame);
702 return -ENOENT;
703 }
704 #endif
705 }
706
707 /* Call finder's callback handler */
708 ret = pf->callback(sc_die, pf);
709
710 /* Since *pf->fb_ops can be a part of frame. we should free it here. */
711 free(frame);
712 pf->fb_ops = NULL;
713
714 return ret;
715 }
716
717 struct find_scope_param {
718 const char *function;
719 const char *file;
720 int line;
721 int diff;
722 Dwarf_Die *die_mem;
723 bool found;
724 };
725
726 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
727 {
728 struct find_scope_param *fsp = data;
729 const char *file;
730 int lno;
731
732 /* Skip if declared file name does not match */
733 if (fsp->file) {
734 file = dwarf_decl_file(fn_die);
735 if (!file || strcmp(fsp->file, file) != 0)
736 return 0;
737 }
738 /* If the function name is given, that's what user expects */
739 if (fsp->function) {
740 if (die_match_name(fn_die, fsp->function)) {
741 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
742 fsp->found = true;
743 return 1;
744 }
745 } else {
746 /* With the line number, find the nearest declared DIE */
747 dwarf_decl_line(fn_die, &lno);
748 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
749 /* Keep a candidate and continue */
750 fsp->diff = fsp->line - lno;
751 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
752 fsp->found = true;
753 }
754 }
755 return 0;
756 }
757
758 /* Return innermost DIE */
759 static int find_inner_scope_cb(Dwarf_Die *fn_die, void *data)
760 {
761 struct find_scope_param *fsp = data;
762
763 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
764 fsp->found = true;
765 return 1;
766 }
767
768 /* Find an appropriate scope fits to given conditions */
769 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
770 {
771 struct find_scope_param fsp = {
772 .function = pf->pev->point.function,
773 .file = pf->fname,
774 .line = pf->lno,
775 .diff = INT_MAX,
776 .die_mem = die_mem,
777 .found = false,
778 };
779 int ret;
780
781 ret = cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb,
782 &fsp);
783 if (!ret && !fsp.found)
784 cu_walk_functions_at(&pf->cu_die, pf->addr,
785 find_inner_scope_cb, &fsp);
786
787 return fsp.found ? die_mem : NULL;
788 }
789
790 static int probe_point_line_walker(const char *fname, int lineno,
791 Dwarf_Addr addr, void *data)
792 {
793 struct probe_finder *pf = data;
794 Dwarf_Die *sc_die, die_mem;
795 int ret;
796
797 if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
798 return 0;
799
800 pf->addr = addr;
801 sc_die = find_best_scope(pf, &die_mem);
802 if (!sc_die) {
803 pr_warning("Failed to find scope of probe point.\n");
804 return -ENOENT;
805 }
806
807 ret = call_probe_finder(sc_die, pf);
808
809 /* Continue if no error, because the line will be in inline function */
810 return ret < 0 ? ret : 0;
811 }
812
813 /* Find probe point from its line number */
814 static int find_probe_point_by_line(struct probe_finder *pf)
815 {
816 return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
817 }
818
819 /* Find lines which match lazy pattern */
820 static int find_lazy_match_lines(struct intlist *list,
821 const char *fname, const char *pat)
822 {
823 FILE *fp;
824 char *line = NULL;
825 size_t line_len;
826 ssize_t len;
827 int count = 0, linenum = 1;
828 char sbuf[STRERR_BUFSIZE];
829
830 fp = fopen(fname, "r");
831 if (!fp) {
832 pr_warning("Failed to open %s: %s\n", fname,
833 str_error_r(errno, sbuf, sizeof(sbuf)));
834 return -errno;
835 }
836
837 while ((len = getline(&line, &line_len, fp)) > 0) {
838
839 if (line[len - 1] == '\n')
840 line[len - 1] = '\0';
841
842 if (strlazymatch(line, pat)) {
843 intlist__add(list, linenum);
844 count++;
845 }
846 linenum++;
847 }
848
849 if (ferror(fp))
850 count = -errno;
851 free(line);
852 fclose(fp);
853
854 if (count == 0)
855 pr_debug("No matched lines found in %s.\n", fname);
856 return count;
857 }
858
859 static int probe_point_lazy_walker(const char *fname, int lineno,
860 Dwarf_Addr addr, void *data)
861 {
862 struct probe_finder *pf = data;
863 Dwarf_Die *sc_die, die_mem;
864 int ret;
865
866 if (!intlist__has_entry(pf->lcache, lineno) ||
867 strtailcmp(fname, pf->fname) != 0)
868 return 0;
869
870 pr_debug("Probe line found: line:%d addr:0x%llx\n",
871 lineno, (unsigned long long)addr);
872 pf->addr = addr;
873 pf->lno = lineno;
874 sc_die = find_best_scope(pf, &die_mem);
875 if (!sc_die) {
876 pr_warning("Failed to find scope of probe point.\n");
877 return -ENOENT;
878 }
879
880 ret = call_probe_finder(sc_die, pf);
881
882 /*
883 * Continue if no error, because the lazy pattern will match
884 * to other lines
885 */
886 return ret < 0 ? ret : 0;
887 }
888
889 /* Find probe points from lazy pattern */
890 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
891 {
892 int ret = 0;
893 char *fpath;
894
895 if (intlist__empty(pf->lcache)) {
896 const char *comp_dir;
897
898 comp_dir = cu_get_comp_dir(&pf->cu_die);
899 ret = get_real_path(pf->fname, comp_dir, &fpath);
900 if (ret < 0) {
901 pr_warning("Failed to find source file path.\n");
902 return ret;
903 }
904
905 /* Matching lazy line pattern */
906 ret = find_lazy_match_lines(pf->lcache, fpath,
907 pf->pev->point.lazy_line);
908 free(fpath);
909 if (ret <= 0)
910 return ret;
911 }
912
913 return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
914 }
915
916 static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
917 {
918 struct perf_probe_point *pp = &pf->pev->point;
919
920 /* Not uprobe? */
921 if (!pf->pev->uprobes)
922 return;
923
924 /* Compiled with optimization? */
925 if (die_is_optimized_target(&pf->cu_die))
926 return;
927
928 /* Don't know entrypc? */
929 if (!pf->addr)
930 return;
931
932 /* Only FUNC and FUNC@SRC are eligible. */
933 if (!pp->function || pp->line || pp->retprobe || pp->lazy_line ||
934 pp->offset || pp->abs_address)
935 return;
936
937 /* Not interested in func parameter? */
938 if (!perf_probe_with_var(pf->pev))
939 return;
940
941 pr_info("Target program is compiled without optimization. Skipping prologue.\n"
942 "Probe on address 0x%" PRIx64 " to force probing at the function entry.\n\n",
943 pf->addr);
944
945 die_skip_prologue(sp_die, &pf->cu_die, &pf->addr);
946 }
947
948 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
949 {
950 struct probe_finder *pf = data;
951 struct perf_probe_point *pp = &pf->pev->point;
952 Dwarf_Addr addr;
953 int ret;
954
955 if (pp->lazy_line)
956 ret = find_probe_point_lazy(in_die, pf);
957 else {
958 /* Get probe address */
959 if (die_entrypc(in_die, &addr) != 0) {
960 pr_warning("Failed to get entry address of %s.\n",
961 dwarf_diename(in_die));
962 return -ENOENT;
963 }
964 if (addr == 0) {
965 pr_debug("%s has no valid entry address. skipped.\n",
966 dwarf_diename(in_die));
967 return -ENOENT;
968 }
969 pf->addr = addr;
970 pf->addr += pp->offset;
971 pr_debug("found inline addr: 0x%jx\n",
972 (uintmax_t)pf->addr);
973
974 ret = call_probe_finder(in_die, pf);
975 }
976
977 return ret;
978 }
979
980 /* Callback parameter with return value for libdw */
981 struct dwarf_callback_param {
982 void *data;
983 int retval;
984 };
985
986 /* Search function from function name */
987 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
988 {
989 struct dwarf_callback_param *param = data;
990 struct probe_finder *pf = param->data;
991 struct perf_probe_point *pp = &pf->pev->point;
992
993 /* Check tag and diename */
994 if (!die_is_func_def(sp_die) ||
995 !die_match_name(sp_die, pp->function))
996 return DWARF_CB_OK;
997
998 /* Check declared file */
999 if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
1000 return DWARF_CB_OK;
1001
1002 pr_debug("Matched function: %s [%lx]\n", dwarf_diename(sp_die),
1003 (unsigned long)dwarf_dieoffset(sp_die));
1004 pf->fname = dwarf_decl_file(sp_die);
1005 if (pp->line) { /* Function relative line */
1006 dwarf_decl_line(sp_die, &pf->lno);
1007 pf->lno += pp->line;
1008 param->retval = find_probe_point_by_line(pf);
1009 } else if (die_is_func_instance(sp_die)) {
1010 /* Instances always have the entry address */
1011 die_entrypc(sp_die, &pf->addr);
1012 /* But in some case the entry address is 0 */
1013 if (pf->addr == 0) {
1014 pr_debug("%s has no entry PC. Skipped\n",
1015 dwarf_diename(sp_die));
1016 param->retval = 0;
1017 /* Real function */
1018 } else if (pp->lazy_line)
1019 param->retval = find_probe_point_lazy(sp_die, pf);
1020 else {
1021 skip_prologue(sp_die, pf);
1022 pf->addr += pp->offset;
1023 /* TODO: Check the address in this function */
1024 param->retval = call_probe_finder(sp_die, pf);
1025 }
1026 } else if (!probe_conf.no_inlines) {
1027 /* Inlined function: search instances */
1028 param->retval = die_walk_instances(sp_die,
1029 probe_point_inline_cb, (void *)pf);
1030 /* This could be a non-existed inline definition */
1031 if (param->retval == -ENOENT)
1032 param->retval = 0;
1033 }
1034
1035 /* We need to find other candidates */
1036 if (strisglob(pp->function) && param->retval >= 0) {
1037 param->retval = 0; /* We have to clear the result */
1038 return DWARF_CB_OK;
1039 }
1040
1041 return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1042 }
1043
1044 static int find_probe_point_by_func(struct probe_finder *pf)
1045 {
1046 struct dwarf_callback_param _param = {.data = (void *)pf,
1047 .retval = 0};
1048 dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1049 return _param.retval;
1050 }
1051
1052 struct pubname_callback_param {
1053 char *function;
1054 char *file;
1055 Dwarf_Die *cu_die;
1056 Dwarf_Die *sp_die;
1057 int found;
1058 };
1059
1060 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1061 {
1062 struct pubname_callback_param *param = data;
1063
1064 if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1065 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1066 return DWARF_CB_OK;
1067
1068 if (die_match_name(param->sp_die, param->function)) {
1069 if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1070 return DWARF_CB_OK;
1071
1072 if (param->file &&
1073 strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1074 return DWARF_CB_OK;
1075
1076 param->found = 1;
1077 return DWARF_CB_ABORT;
1078 }
1079 }
1080
1081 return DWARF_CB_OK;
1082 }
1083
1084 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1085 struct probe_finder *pf)
1086 {
1087 struct perf_probe_point *pp = &pf->pev->point;
1088 Dwarf_Off off, noff;
1089 size_t cuhl;
1090 Dwarf_Die *diep;
1091 int ret = 0;
1092
1093 off = 0;
1094 pf->lcache = intlist__new(NULL);
1095 if (!pf->lcache)
1096 return -ENOMEM;
1097
1098 /* Fastpath: lookup by function name from .debug_pubnames section */
1099 if (pp->function && !strisglob(pp->function)) {
1100 struct pubname_callback_param pubname_param = {
1101 .function = pp->function,
1102 .file = pp->file,
1103 .cu_die = &pf->cu_die,
1104 .sp_die = &pf->sp_die,
1105 .found = 0,
1106 };
1107 struct dwarf_callback_param probe_param = {
1108 .data = pf,
1109 };
1110
1111 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1112 &pubname_param, 0);
1113 if (pubname_param.found) {
1114 ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1115 if (ret)
1116 goto found;
1117 }
1118 }
1119
1120 /* Loop on CUs (Compilation Unit) */
1121 while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1122 /* Get the DIE(Debugging Information Entry) of this CU */
1123 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1124 if (!diep)
1125 continue;
1126
1127 /* Check if target file is included. */
1128 if (pp->file)
1129 pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1130 else
1131 pf->fname = NULL;
1132
1133 if (!pp->file || pf->fname) {
1134 if (pp->function)
1135 ret = find_probe_point_by_func(pf);
1136 else if (pp->lazy_line)
1137 ret = find_probe_point_lazy(&pf->cu_die, pf);
1138 else {
1139 pf->lno = pp->line;
1140 ret = find_probe_point_by_line(pf);
1141 }
1142 if (ret < 0)
1143 break;
1144 }
1145 off = noff;
1146 }
1147
1148 found:
1149 intlist__delete(pf->lcache);
1150 pf->lcache = NULL;
1151
1152 return ret;
1153 }
1154
1155 /* Find probe points from debuginfo */
1156 static int debuginfo__find_probes(struct debuginfo *dbg,
1157 struct probe_finder *pf)
1158 {
1159 int ret = 0;
1160 Elf *elf;
1161 GElf_Ehdr ehdr;
1162
1163 if (pf->cfi_eh || pf->cfi_dbg)
1164 return debuginfo__find_probe_location(dbg, pf);
1165
1166 /* Get the call frame information from this dwarf */
1167 elf = dwarf_getelf(dbg->dbg);
1168 if (elf == NULL)
1169 return -EINVAL;
1170
1171 if (gelf_getehdr(elf, &ehdr) == NULL)
1172 return -EINVAL;
1173
1174 pf->machine = ehdr.e_machine;
1175
1176 #if _ELFUTILS_PREREQ(0, 142)
1177 do {
1178 GElf_Shdr shdr;
1179
1180 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1181 shdr.sh_type == SHT_PROGBITS)
1182 pf->cfi_eh = dwarf_getcfi_elf(elf);
1183
1184 pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1185 } while (0);
1186 #endif
1187
1188 ret = debuginfo__find_probe_location(dbg, pf);
1189 return ret;
1190 }
1191
1192 struct local_vars_finder {
1193 struct probe_finder *pf;
1194 struct perf_probe_arg *args;
1195 bool vars;
1196 int max_args;
1197 int nargs;
1198 int ret;
1199 };
1200
1201 /* Collect available variables in this scope */
1202 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1203 {
1204 struct local_vars_finder *vf = data;
1205 struct probe_finder *pf = vf->pf;
1206 int tag;
1207
1208 tag = dwarf_tag(die_mem);
1209 if (tag == DW_TAG_formal_parameter ||
1210 (tag == DW_TAG_variable && vf->vars)) {
1211 if (convert_variable_location(die_mem, vf->pf->addr,
1212 vf->pf->fb_ops, &pf->sp_die,
1213 pf->machine, NULL) == 0) {
1214 vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1215 if (vf->args[vf->nargs].var == NULL) {
1216 vf->ret = -ENOMEM;
1217 return DIE_FIND_CB_END;
1218 }
1219 pr_debug(" %s", vf->args[vf->nargs].var);
1220 vf->nargs++;
1221 }
1222 }
1223
1224 if (dwarf_haspc(die_mem, vf->pf->addr))
1225 return DIE_FIND_CB_CONTINUE;
1226 else
1227 return DIE_FIND_CB_SIBLING;
1228 }
1229
1230 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1231 struct perf_probe_arg *args)
1232 {
1233 Dwarf_Die die_mem;
1234 int i;
1235 int n = 0;
1236 struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1237 .max_args = MAX_PROBE_ARGS, .ret = 0};
1238
1239 for (i = 0; i < pf->pev->nargs; i++) {
1240 /* var never be NULL */
1241 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1242 vf.vars = true;
1243 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1244 /* Copy normal argument */
1245 args[n] = pf->pev->args[i];
1246 n++;
1247 continue;
1248 }
1249 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1250 vf.nargs = n;
1251 /* Special local variables */
1252 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1253 &die_mem);
1254 pr_debug(" (%d)\n", vf.nargs - n);
1255 if (vf.ret < 0)
1256 return vf.ret;
1257 n = vf.nargs;
1258 }
1259 return n;
1260 }
1261
1262 /* Add a found probe point into trace event list */
1263 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1264 {
1265 struct trace_event_finder *tf =
1266 container_of(pf, struct trace_event_finder, pf);
1267 struct perf_probe_point *pp = &pf->pev->point;
1268 struct probe_trace_event *tev;
1269 struct perf_probe_arg *args = NULL;
1270 int ret, i;
1271
1272 /* Check number of tevs */
1273 if (tf->ntevs == tf->max_tevs) {
1274 pr_warning("Too many( > %d) probe point found.\n",
1275 tf->max_tevs);
1276 return -ERANGE;
1277 }
1278 tev = &tf->tevs[tf->ntevs++];
1279
1280 /* Trace point should be converted from subprogram DIE */
1281 ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1282 pp->retprobe, pp->function, &tev->point);
1283 if (ret < 0)
1284 goto end;
1285
1286 tev->point.realname = strdup(dwarf_diename(sc_die));
1287 if (!tev->point.realname) {
1288 ret = -ENOMEM;
1289 goto end;
1290 }
1291
1292 pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1293 tev->point.offset);
1294
1295 /* Expand special probe argument if exist */
1296 args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1297 if (args == NULL) {
1298 ret = -ENOMEM;
1299 goto end;
1300 }
1301
1302 ret = expand_probe_args(sc_die, pf, args);
1303 if (ret < 0)
1304 goto end;
1305
1306 tev->nargs = ret;
1307 tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1308 if (tev->args == NULL) {
1309 ret = -ENOMEM;
1310 goto end;
1311 }
1312
1313 /* Find each argument */
1314 for (i = 0; i < tev->nargs; i++) {
1315 pf->pvar = &args[i];
1316 pf->tvar = &tev->args[i];
1317 /* Variable should be found from scope DIE */
1318 ret = find_variable(sc_die, pf);
1319 if (ret != 0)
1320 break;
1321 }
1322
1323 end:
1324 if (ret) {
1325 clear_probe_trace_event(tev);
1326 tf->ntevs--;
1327 }
1328 free(args);
1329 return ret;
1330 }
1331
1332 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1333 int debuginfo__find_trace_events(struct debuginfo *dbg,
1334 struct perf_probe_event *pev,
1335 struct probe_trace_event **tevs)
1336 {
1337 struct trace_event_finder tf = {
1338 .pf = {.pev = pev, .callback = add_probe_trace_event},
1339 .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1340 int ret, i;
1341
1342 /* Allocate result tevs array */
1343 *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1344 if (*tevs == NULL)
1345 return -ENOMEM;
1346
1347 tf.tevs = *tevs;
1348 tf.ntevs = 0;
1349
1350 ret = debuginfo__find_probes(dbg, &tf.pf);
1351 if (ret < 0) {
1352 for (i = 0; i < tf.ntevs; i++)
1353 clear_probe_trace_event(&tf.tevs[i]);
1354 zfree(tevs);
1355 return ret;
1356 }
1357
1358 return (ret < 0) ? ret : tf.ntevs;
1359 }
1360
1361 /* Collect available variables in this scope */
1362 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1363 {
1364 struct available_var_finder *af = data;
1365 struct variable_list *vl;
1366 struct strbuf buf = STRBUF_INIT;
1367 int tag, ret;
1368
1369 vl = &af->vls[af->nvls - 1];
1370
1371 tag = dwarf_tag(die_mem);
1372 if (tag == DW_TAG_formal_parameter ||
1373 tag == DW_TAG_variable) {
1374 ret = convert_variable_location(die_mem, af->pf.addr,
1375 af->pf.fb_ops, &af->pf.sp_die,
1376 af->pf.machine, NULL);
1377 if (ret == 0 || ret == -ERANGE) {
1378 int ret2;
1379 bool externs = !af->child;
1380
1381 if (strbuf_init(&buf, 64) < 0)
1382 goto error;
1383
1384 if (probe_conf.show_location_range) {
1385 if (!externs)
1386 ret2 = strbuf_add(&buf,
1387 ret ? "[INV]\t" : "[VAL]\t", 6);
1388 else
1389 ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1390 if (ret2)
1391 goto error;
1392 }
1393
1394 ret2 = die_get_varname(die_mem, &buf);
1395
1396 if (!ret2 && probe_conf.show_location_range &&
1397 !externs) {
1398 if (strbuf_addch(&buf, '\t') < 0)
1399 goto error;
1400 ret2 = die_get_var_range(&af->pf.sp_die,
1401 die_mem, &buf);
1402 }
1403
1404 pr_debug("Add new var: %s\n", buf.buf);
1405 if (ret2 == 0) {
1406 strlist__add(vl->vars,
1407 strbuf_detach(&buf, NULL));
1408 }
1409 strbuf_release(&buf);
1410 }
1411 }
1412
1413 if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1414 return DIE_FIND_CB_CONTINUE;
1415 else
1416 return DIE_FIND_CB_SIBLING;
1417 error:
1418 strbuf_release(&buf);
1419 pr_debug("Error in strbuf\n");
1420 return DIE_FIND_CB_END;
1421 }
1422
1423 static bool available_var_finder_overlap(struct available_var_finder *af)
1424 {
1425 int i;
1426
1427 for (i = 0; i < af->nvls; i++) {
1428 if (af->pf.addr == af->vls[i].point.address)
1429 return true;
1430 }
1431 return false;
1432
1433 }
1434
1435 /* Add a found vars into available variables list */
1436 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1437 {
1438 struct available_var_finder *af =
1439 container_of(pf, struct available_var_finder, pf);
1440 struct perf_probe_point *pp = &pf->pev->point;
1441 struct variable_list *vl;
1442 Dwarf_Die die_mem;
1443 int ret;
1444
1445 /*
1446 * For some reason (e.g. different column assigned to same address),
1447 * this callback can be called with the address which already passed.
1448 * Ignore it first.
1449 */
1450 if (available_var_finder_overlap(af))
1451 return 0;
1452
1453 /* Check number of tevs */
1454 if (af->nvls == af->max_vls) {
1455 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1456 return -ERANGE;
1457 }
1458 vl = &af->vls[af->nvls++];
1459
1460 /* Trace point should be converted from subprogram DIE */
1461 ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1462 pp->retprobe, pp->function, &vl->point);
1463 if (ret < 0)
1464 return ret;
1465
1466 pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1467 vl->point.offset);
1468
1469 /* Find local variables */
1470 vl->vars = strlist__new(NULL, NULL);
1471 if (vl->vars == NULL)
1472 return -ENOMEM;
1473 af->child = true;
1474 die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1475
1476 /* Find external variables */
1477 if (!probe_conf.show_ext_vars)
1478 goto out;
1479 /* Don't need to search child DIE for external vars. */
1480 af->child = false;
1481 die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1482
1483 out:
1484 if (strlist__empty(vl->vars)) {
1485 strlist__delete(vl->vars);
1486 vl->vars = NULL;
1487 }
1488
1489 return ret;
1490 }
1491
1492 /*
1493 * Find available variables at given probe point
1494 * Return the number of found probe points. Return 0 if there is no
1495 * matched probe point. Return <0 if an error occurs.
1496 */
1497 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1498 struct perf_probe_event *pev,
1499 struct variable_list **vls)
1500 {
1501 struct available_var_finder af = {
1502 .pf = {.pev = pev, .callback = add_available_vars},
1503 .mod = dbg->mod,
1504 .max_vls = probe_conf.max_probes};
1505 int ret;
1506
1507 /* Allocate result vls array */
1508 *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1509 if (*vls == NULL)
1510 return -ENOMEM;
1511
1512 af.vls = *vls;
1513 af.nvls = 0;
1514
1515 ret = debuginfo__find_probes(dbg, &af.pf);
1516 if (ret < 0) {
1517 /* Free vlist for error */
1518 while (af.nvls--) {
1519 zfree(&af.vls[af.nvls].point.symbol);
1520 strlist__delete(af.vls[af.nvls].vars);
1521 }
1522 zfree(vls);
1523 return ret;
1524 }
1525
1526 return (ret < 0) ? ret : af.nvls;
1527 }
1528
1529 /* For the kernel module, we need a special code to get a DIE */
1530 int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
1531 bool adjust_offset)
1532 {
1533 int n, i;
1534 Elf32_Word shndx;
1535 Elf_Scn *scn;
1536 Elf *elf;
1537 GElf_Shdr mem, *shdr;
1538 const char *p;
1539
1540 elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1541 if (!elf)
1542 return -EINVAL;
1543
1544 /* Get the number of relocations */
1545 n = dwfl_module_relocations(dbg->mod);
1546 if (n < 0)
1547 return -ENOENT;
1548 /* Search the relocation related .text section */
1549 for (i = 0; i < n; i++) {
1550 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1551 if (strcmp(p, ".text") == 0) {
1552 /* OK, get the section header */
1553 scn = elf_getscn(elf, shndx);
1554 if (!scn)
1555 return -ENOENT;
1556 shdr = gelf_getshdr(scn, &mem);
1557 if (!shdr)
1558 return -ENOENT;
1559 *offs = shdr->sh_addr;
1560 if (adjust_offset)
1561 *offs -= shdr->sh_offset;
1562 }
1563 }
1564 return 0;
1565 }
1566
1567 /* Reverse search */
1568 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1569 struct perf_probe_point *ppt)
1570 {
1571 Dwarf_Die cudie, spdie, indie;
1572 Dwarf_Addr _addr = 0, baseaddr = 0;
1573 const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1574 int baseline = 0, lineno = 0, ret = 0;
1575
1576 /* We always need to relocate the address for aranges */
1577 if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0)
1578 addr += baseaddr;
1579 /* Find cu die */
1580 if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1581 pr_warning("Failed to find debug information for address %lx\n",
1582 addr);
1583 ret = -EINVAL;
1584 goto end;
1585 }
1586
1587 /* Find a corresponding line (filename and lineno) */
1588 cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1589 /* Don't care whether it failed or not */
1590
1591 /* Find a corresponding function (name, baseline and baseaddr) */
1592 if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1593 /* Get function entry information */
1594 func = basefunc = dwarf_diename(&spdie);
1595 if (!func ||
1596 die_entrypc(&spdie, &baseaddr) != 0 ||
1597 dwarf_decl_line(&spdie, &baseline) != 0) {
1598 lineno = 0;
1599 goto post;
1600 }
1601
1602 fname = dwarf_decl_file(&spdie);
1603 if (addr == (unsigned long)baseaddr) {
1604 /* Function entry - Relative line number is 0 */
1605 lineno = baseline;
1606 goto post;
1607 }
1608
1609 /* Track down the inline functions step by step */
1610 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1611 &indie)) {
1612 /* There is an inline function */
1613 if (die_entrypc(&indie, &_addr) == 0 &&
1614 _addr == addr) {
1615 /*
1616 * addr is at an inline function entry.
1617 * In this case, lineno should be the call-site
1618 * line number. (overwrite lineinfo)
1619 */
1620 lineno = die_get_call_lineno(&indie);
1621 fname = die_get_call_file(&indie);
1622 break;
1623 } else {
1624 /*
1625 * addr is in an inline function body.
1626 * Since lineno points one of the lines
1627 * of the inline function, baseline should
1628 * be the entry line of the inline function.
1629 */
1630 tmp = dwarf_diename(&indie);
1631 if (!tmp ||
1632 dwarf_decl_line(&indie, &baseline) != 0)
1633 break;
1634 func = tmp;
1635 spdie = indie;
1636 }
1637 }
1638 /* Verify the lineno and baseline are in a same file */
1639 tmp = dwarf_decl_file(&spdie);
1640 if (!tmp || strcmp(tmp, fname) != 0)
1641 lineno = 0;
1642 }
1643
1644 post:
1645 /* Make a relative line number or an offset */
1646 if (lineno)
1647 ppt->line = lineno - baseline;
1648 else if (basefunc) {
1649 ppt->offset = addr - (unsigned long)baseaddr;
1650 func = basefunc;
1651 }
1652
1653 /* Duplicate strings */
1654 if (func) {
1655 ppt->function = strdup(func);
1656 if (ppt->function == NULL) {
1657 ret = -ENOMEM;
1658 goto end;
1659 }
1660 }
1661 if (fname) {
1662 ppt->file = strdup(fname);
1663 if (ppt->file == NULL) {
1664 zfree(&ppt->function);
1665 ret = -ENOMEM;
1666 goto end;
1667 }
1668 }
1669 end:
1670 if (ret == 0 && (fname || func))
1671 ret = 1; /* Found a point */
1672 return ret;
1673 }
1674
1675 /* Add a line and store the src path */
1676 static int line_range_add_line(const char *src, unsigned int lineno,
1677 struct line_range *lr)
1678 {
1679 /* Copy source path */
1680 if (!lr->path) {
1681 lr->path = strdup(src);
1682 if (lr->path == NULL)
1683 return -ENOMEM;
1684 }
1685 return intlist__add(lr->line_list, lineno);
1686 }
1687
1688 static int line_range_walk_cb(const char *fname, int lineno,
1689 Dwarf_Addr addr __maybe_unused,
1690 void *data)
1691 {
1692 struct line_finder *lf = data;
1693 int err;
1694
1695 if ((strtailcmp(fname, lf->fname) != 0) ||
1696 (lf->lno_s > lineno || lf->lno_e < lineno))
1697 return 0;
1698
1699 err = line_range_add_line(fname, lineno, lf->lr);
1700 if (err < 0 && err != -EEXIST)
1701 return err;
1702
1703 return 0;
1704 }
1705
1706 /* Find line range from its line number */
1707 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1708 {
1709 int ret;
1710
1711 ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1712
1713 /* Update status */
1714 if (ret >= 0)
1715 if (!intlist__empty(lf->lr->line_list))
1716 ret = lf->found = 1;
1717 else
1718 ret = 0; /* Lines are not found */
1719 else {
1720 zfree(&lf->lr->path);
1721 }
1722 return ret;
1723 }
1724
1725 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1726 {
1727 int ret = find_line_range_by_line(in_die, data);
1728
1729 /*
1730 * We have to check all instances of inlined function, because
1731 * some execution paths can be optimized out depends on the
1732 * function argument of instances. However, if an error occurs,
1733 * it should be handled by the caller.
1734 */
1735 return ret < 0 ? ret : 0;
1736 }
1737
1738 /* Search function definition from function name */
1739 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1740 {
1741 struct dwarf_callback_param *param = data;
1742 struct line_finder *lf = param->data;
1743 struct line_range *lr = lf->lr;
1744
1745 /* Check declared file */
1746 if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1747 return DWARF_CB_OK;
1748
1749 if (die_is_func_def(sp_die) &&
1750 die_match_name(sp_die, lr->function)) {
1751 lf->fname = dwarf_decl_file(sp_die);
1752 dwarf_decl_line(sp_die, &lr->offset);
1753 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1754 lf->lno_s = lr->offset + lr->start;
1755 if (lf->lno_s < 0) /* Overflow */
1756 lf->lno_s = INT_MAX;
1757 lf->lno_e = lr->offset + lr->end;
1758 if (lf->lno_e < 0) /* Overflow */
1759 lf->lno_e = INT_MAX;
1760 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1761 lr->start = lf->lno_s;
1762 lr->end = lf->lno_e;
1763 if (!die_is_func_instance(sp_die))
1764 param->retval = die_walk_instances(sp_die,
1765 line_range_inline_cb, lf);
1766 else
1767 param->retval = find_line_range_by_line(sp_die, lf);
1768 return DWARF_CB_ABORT;
1769 }
1770 return DWARF_CB_OK;
1771 }
1772
1773 static int find_line_range_by_func(struct line_finder *lf)
1774 {
1775 struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1776 dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1777 return param.retval;
1778 }
1779
1780 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1781 {
1782 struct line_finder lf = {.lr = lr, .found = 0};
1783 int ret = 0;
1784 Dwarf_Off off = 0, noff;
1785 size_t cuhl;
1786 Dwarf_Die *diep;
1787 const char *comp_dir;
1788
1789 /* Fastpath: lookup by function name from .debug_pubnames section */
1790 if (lr->function) {
1791 struct pubname_callback_param pubname_param = {
1792 .function = lr->function, .file = lr->file,
1793 .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1794 struct dwarf_callback_param line_range_param = {
1795 .data = (void *)&lf, .retval = 0};
1796
1797 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1798 &pubname_param, 0);
1799 if (pubname_param.found) {
1800 line_range_search_cb(&lf.sp_die, &line_range_param);
1801 if (lf.found)
1802 goto found;
1803 }
1804 }
1805
1806 /* Loop on CUs (Compilation Unit) */
1807 while (!lf.found && ret >= 0) {
1808 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1809 NULL, NULL, NULL) != 0)
1810 break;
1811
1812 /* Get the DIE(Debugging Information Entry) of this CU */
1813 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1814 if (!diep)
1815 continue;
1816
1817 /* Check if target file is included. */
1818 if (lr->file)
1819 lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1820 else
1821 lf.fname = 0;
1822
1823 if (!lr->file || lf.fname) {
1824 if (lr->function)
1825 ret = find_line_range_by_func(&lf);
1826 else {
1827 lf.lno_s = lr->start;
1828 lf.lno_e = lr->end;
1829 ret = find_line_range_by_line(NULL, &lf);
1830 }
1831 }
1832 off = noff;
1833 }
1834
1835 found:
1836 /* Store comp_dir */
1837 if (lf.found) {
1838 comp_dir = cu_get_comp_dir(&lf.cu_die);
1839 if (comp_dir) {
1840 lr->comp_dir = strdup(comp_dir);
1841 if (!lr->comp_dir)
1842 ret = -ENOMEM;
1843 }
1844 }
1845
1846 pr_debug("path: %s\n", lr->path);
1847 return (ret < 0) ? ret : lf.found;
1848 }
1849
1850 /*
1851 * Find a src file from a DWARF tag path. Prepend optional source path prefix
1852 * and chop off leading directories that do not exist. Result is passed back as
1853 * a newly allocated path on success.
1854 * Return 0 if file was found and readable, -errno otherwise.
1855 */
1856 int get_real_path(const char *raw_path, const char *comp_dir,
1857 char **new_path)
1858 {
1859 const char *prefix = symbol_conf.source_prefix;
1860
1861 if (!prefix) {
1862 if (raw_path[0] != '/' && comp_dir)
1863 /* If not an absolute path, try to use comp_dir */
1864 prefix = comp_dir;
1865 else {
1866 if (access(raw_path, R_OK) == 0) {
1867 *new_path = strdup(raw_path);
1868 return *new_path ? 0 : -ENOMEM;
1869 } else
1870 return -errno;
1871 }
1872 }
1873
1874 *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1875 if (!*new_path)
1876 return -ENOMEM;
1877
1878 for (;;) {
1879 sprintf(*new_path, "%s/%s", prefix, raw_path);
1880
1881 if (access(*new_path, R_OK) == 0)
1882 return 0;
1883
1884 if (!symbol_conf.source_prefix) {
1885 /* In case of searching comp_dir, don't retry */
1886 zfree(new_path);
1887 return -errno;
1888 }
1889
1890 switch (errno) {
1891 case ENAMETOOLONG:
1892 case ENOENT:
1893 case EROFS:
1894 case EFAULT:
1895 raw_path = strchr(++raw_path, '/');
1896 if (!raw_path) {
1897 zfree(new_path);
1898 return -ENOENT;
1899 }
1900 continue;
1901
1902 default:
1903 zfree(new_path);
1904 return -errno;
1905 }
1906 }
1907 }
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